What Material are the Bypass Valve and Valve Head Made of? December 18, 2023 18:08 Updated They are made of a plastic called Celcon and both products are NSF stamped. Bypass Valve: Valve Head: Related articles How Does a Bypass Valve Work? Why does my water smell after installing a softener? How Much Resin Should Be in the Tank? Morton Product Insert (QR Code) How do you know when it's time to upgrade your softener?